PSI - Issue 78

Agnese Natali et al. / Procedia Structural Integrity 78 (2026) 2015–2021

2016

design and retrofitting (Caprili et al. (2024), Caprili et al. (2021), Caprili et al. (2022)), recent developments in laser cutting technology have enabled the creation of high-precision slots in CHS profiles, allowing the use of passing through plates to enhance joint performance (Kanyilmaz (2018)). In previous findings, these solutions showed a very good behaviour under vertical load (Couchaux et al. (2021), Piscini et al. (2021)), but very poor under horizontal load, also due to the not efficient realization of the welding connecting the nodal plate to the column (Piscini et al. (2020), LASTEICON Project (2025)). This study focuses on the monotonic seismic response of composite CHS-to-I joints with passing-through plates, specifically in a configuration where the column is filled with concrete and the I-beam supports a cast-in-place composite slab connected through shear studs. The design of the weld was renewed thanks to additional studies on the performance of different types of weld on elements connected through laser-cut slots (Safaeifaegh et al. (2025)), and their realisation has been performed with high accuracy. This new design/realisation approach has also been applied to other components connected adopting the laser-cutting technology (Menghini et al. (2023), Das et al. (2024)). The objective is to evaluate the structural performance of this enhanced composite configuration under monotonic lateral loading, with a focus on weld behaviour, slab cracking, and interaction effects. Experimental testing and finite element modelling were conducted to analyse the behaviour of the joint and validate numerical strategies for further parametric analysis. 2. Design of the specimen and the test set up 2.1. Specimen Description The test specimens analysed in this study represent a two-way beam-to-column joint composed of a CHS column (355.6 mm × 10 mm, S355) with welded passing-through plates and two IPE400 steel beams also in S355. The column was filled with concrete (C25/30), and a slab was cast in place on top of a metallic corrugated sheet, connected to the beams via shear studs. The plates used for the connection included flange plates (180 mm wide, 16 mm thick) and web plates (260 mm wide, 10 mm thick), both of which were inserted through laser-cut openings in the column wall and welded using fillet welds. Fig.1 gathers and illustrates the main dimensions of the specimens and the rebars configuration in the slab.

Fig. 1. Composite specimen’s configuration.